package com.tangding.common.holder;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * @description 
 *
 * @author Ranger
 * @version 2017年7月7日_下午4:57:19
 *
 */
@Component
public class SpringContextHolder implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */
    public void setApplicationContext(ApplicationContext applicationContext) {
        SpringContextHolder.applicationContext = applicationContext;
    }

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
        checkApplicationContext();
        return applicationContext;
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        checkApplicationContext();
        if (!applicationContext.containsBean(name)) {
			return null;
		}
        return (T) applicationContext.getBean(name);
    }
    
    /**
     * 当前context中是否存在指定key
     * 
     * @param name
     * @return
     */
    public static boolean containsBean(String name) {
        checkApplicationContext();
        return applicationContext.containsBean(name);
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
	public static <T> T getBean(Class<T> clazz) {
        checkApplicationContext();
        
        String className = clazz.getSimpleName();
        if (applicationContext.containsBean(className)) {
			return getBean(className);
		}
        
        String cn = className.substring(0, 1).toLowerCase() + className.substring(1);
        if (applicationContext.containsBean(cn)) {
        	return getBean(cn);
		}
        return applicationContext.getBean(clazz);
    }
    
    /**
     * 清除applicationContext静态变量.
     */
    public static void cleanApplicationContext() {
        applicationContext = null;
    }

    private static void checkApplicationContext() {
        if (applicationContext == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
        }
    }

}
